Paul Scotney, head of security at the British Horseracing Authority which concluded its latest investigation into corruption on Wednesday. Photograph: Graham Turner for the Guardian

Betting turnover on racing is expected to drop as a consequence of the latest corruption case, which ended on Wednesday with four jockeys being banned from the sport. That is the view of one leading firm of bookmakers, though the sport's ruling body made an effort to reassure punters that racing's record on integrity is at least as good as that of any other sport.

"Yet again, racing has got out of the racing pages for the wrong reasons," said David Williams, a spokesman for Ladbrokes. "It's bad news for everyone because mud sticks, regardless of the detail.

"I hope we can amplify the fact that in rooting out corruption there will be a long-term benefit for racing, because there is no product if there is no integrity. If people do not believe that what they are watching is straight, turnover will plummet."

Williams said there was clear reason from Ladbrokes to believe that turnover had dropped in response to media coverage of previous corruption cases. "It recovers, it's not lasting damage, but it's something that chips away at a sport that is clawing for all the punting pounds it can get."

Kate Miller of William Hill suggested that an immediate decline was unlikely but said that this kind of story could deter a younger audience from taking an interest, causing problems in the longer term.

In the immediate aftermath of the bans, Paul Scotney, the British Horseracing Authority's director of integrity services, made a point of thanking not just Betfair, which has a history of sharing information with the BHA, but also the traditional bookmakers. Williams confirmed that Ladbrokes had helped to further the investigation. "We are very much of the view that we will do whatever we can to expose wrongdoing," he said.

The BHA's spokesman, Robin Mounsey, hoped that punters would not be put off by Wednesday's news, saying they "should continue to have every confidence in British racing as a betting medium".

Mounsey added: "This case is a sign of the efficiency and the range of powers of our integrity department. There are a minority of individuals who are the instigators of conspiracies of this nature and it's our job to isolate them and root them out, and the success of this case shows we are able to tackle that task. Our sophisticated real-time monitoring systems, allied with our relationships with the betting industry, enables us to identify suspicious betting patterns.

"There will always be risk involved in any sport where betting is involved but we have a proven track record in pinpointing any individuals who try to corrupt the sport. We are world leaders in sports regulation and have been the go-to body on several occasions when other sports in Britain are looking for advice on the subject of integrity.

"That's why Paul Scotney, our director of integrity services, is now in Gdansk, where he has been invited by the Polish presidency to address the EU sports directors meeting on the role of good governance in racing."

Mounsey said that the police and the gambling commission had been kept "fully informed" and had been advised of the investigation outcome. The question of whether any criminal prosecution will follow is unlikely to be resolved for some weeks, due to the detail involved.

Kirsty Milczarek is expected to be the only one of the banned jockeys who will appeal. She has until next Friday to do so. Jimmy Quinn's solicitor has indicated that he is likely to serve his six-month ban and return in time for Royal Ascot.